1. Field of the Invention
The present invention relates to a method of and an apparatus for rendering an image representing a fluid motion such as a stream of water or a flow of smoke, a recording medium which stores a program and data for carrying out such an image rendering process, and a program for carrying out such an image rendering process.
2. Description of the Related Art
Recently, various computer graphics (CG) processing techniques including hidden line processing, hidden surface removal, smooth shading, texture mapping, etc. have been in rapid progress in combination with quickly growing hardware technologies.
According to a general CG processing scheme, a plurality of three-dimensional shapes (objects) are generated by three-dimensional modeling of CAD, and a rendering process is performed by applying colors and shades to the objects, adding optical properties including mirror reflection, diffuse reflection, refraction, transparency, etc. to the objects, adding surface patterns to the objects, and plotting images depending on surroundings such as window and scenery reflections and ambient light.
For rendering a fluid motion such as a stream of water or a flow of smoke, for example, it has been attempted to move a number of objects at random and thereafter map an image of water or smoke onto the objects.
Specifically, for processing ordinary polygons, a geometry operation unit performs perspective projection on the vertexes of polygons, and a rendering processor stores the obtained polygons in a display rendering memory.
For example, if a fluid motion is to be rendered by moving n objects at random and then mapping a texture onto the objects, then it is necessary to perform the above process, i.e., the ordinary polygon processing sequence with respect to an object, n times, and, as a result, it is necessary to perform (n×the number of polygon vertexes) perspective projection processes, and also to perform (n×the number of polygons) rendering processes.
In order to render a stream of water or a flow of smoke realistically, therefore, a number of objects need to be prepared, and the period of time required to compute and render those objects increases in proportion to the number of objects involved. Consequently, those objects are displayed on a display monitor at a reduced speed.